Interpolymers of di-(isobutyl carbinol) itaconate and ethyl methacrylate



Patented Apr. 14, 1942 UNITED STATES PATENT OFFICE.

INTERPOLYMEBS 0F vIJI-(ISOBU' FYL CAB- BINOL) ITACONATE AND ETHYL METH- ACRYLATE Gaetano F. DAlelio, Plttsfleld, Mass., a'sslgnor to General Electric Company, a corporation of New York No Drawing. Application September 12, 1939,

Serial N0. 294,497

2 Claims.

This invention relates the production of new materials having valuable and characteristic properties that make them especially suitable for vuse in industry, for example in molding.

, laminating, casting, coating and adhesive applications and for other purposes. The invention is concerned more particularly with compositions of matter comprising an interpolymer of an -crr=c more particularly a p CH C grouping Specifically the invention is concerned with a composition comprising the product of polymerization of a mixture containing di- (isobutyl carblnol) itaconate and ethyl methacrylate in the ratio of, by weight, 5 parts of the former to 95 parts of the latter. 2

The new esters used in practicing this inven tion are itaconic esters in which at least one optically inactive ester group contains five and only five saturated carbons in the alcohol residue.

Examples of such esters. are. mono amyl-- itaconate,

v coon o1n=o CHzCOOCsHn methyl amyl itaconate,

000cm 0Hi=c CHzCOOCtHu J and propyl amyl itaconate,

CHFC

It will be noted that the two last-named esters are mixed esters. The preparation of mixed esters is in general somewhat difllcult and complicated, involving extensive processing and high cost. The mono esters are not difilcult to make but no particular advantages ordinarily accrue from their use in the production of interpolymers. Hence the preferred embodiment of this invention comprises the preparation, and utilization in the production of interpolymers, of optically inactive amylesters of itaconic acid in which both ester groups are identical (symmetrical diesters). Examples of such diesters are optically inactive diamyl itaconate, di-(isobutyl carblnol) itaconate, di-(secondary butyl carblnol) itaconate, di-(diethyl carblnol) itaconate and di-(methyl propyl carblnol) itaconate. The mixed amyl itaconates obtained by esterifying itaconic acid with amyl alcohols derived from chlorinated pentanes also may be polymerized alone or with other polymerizable materials in practicing the present invention. The optically inactive mixed and symmetrical itaconic diesters may be graphically expressed by the formula,

QHFO-(IOOR HICOOR' where R and R are the same or different 0 tically inactive amyl radicals, but preferably are the same. i s

The prior knownmethyl, ethyl and optically active amyl itaconic esters are reported as bein hard, brittle masses in polymeric state. 1 In con trast therewith, the polymerized esters 01' this invention are-soft or rubbery bodies. For example, normal diamyl itaconate gave a rubbery polymer, diethyl carbinol itaconic ester formed a very viscous polymer, while polymeric methyl propyl carbinol itaconic ester was slightly harder than the diethyl carbinol derivative. Secondary butyl carbinol itaconic ester gave-a stiffer polymeric body than didiethyl carbinol) itaconate. While these characteristics are valuable in themselves, greater economic utility is derived by their use in interpolymerization processes, as will become evident asthe description ofthe invention proceeds. I

In carrying the'present invention into effect the amyl itaconates of this invention may be polymerized separately, or mixed with each other, material. The homogeneous and heterogeneous polymers of the invention vary from viscous masses to, rubbery'and hard, solid bodies, depending upon the extent of polymerization and the particular polymerizable or other modifying agent, it any, which is incorporated therewith.

Heat, light, or heat and light may be used to efiect polymerization, although under such conditions the rate of polymerization is relatively slow. Hence, to accelerate the polymerization, I prefer to use'a catalyst, accompanied by heat, light, or heat and light. Examples of catalysts which may be used are oxygen, ozone, hydrogen or mixed with other polymerizable peroxide, sulfuric acid, aluminum chloride, boron fluoride, super-oxides such as aliphatic acyl peroxides, e. g., acetyl peroxide, stearyl peroxide, etc., peroxides of the aromatic acid series, e. g., benzoyl peroxide. Benzoyl peroxide is the preferred catalyst because of its ease of handling, its relative freedom from explosive hazards and its ready solubility in the monomeric or partially polymerized itaconic ester. The rate of polymerization is a function of the temperature and may be carried out at from room temperature 30 C.) to temperatures materially above 100 C., for example about 130 C.

The optically inactive monomeric diamyl esters when polymerized alone form thermoplastic materials, that is materials the shape of which can be easily changed by heat. The softening point, solubility and other properties of these itaconic esters appear to depend upon the structure of the ester chain. As seen from the exmineral oil. This property of high plastic flow can be used to great commercial advantage in molding processes by interpolymerizing these monomers with other bodies of low plastic flow,

thereby imparting the desired flow characteristics to the end-product.

In other cases, for examplewhere it is desired to raise the softening point, to decrease the britmerized itaconic esters, for example dimethyl' itaconate, diethyl itaconate, itaconic esters of unsaturated alcohols, for instance diallyl itaconate, etc., vinyl and allyl esters of saturated and unsaturated monoand poly-carboxylic acids,

. etc., more particularly polymerizable materials containing a C HFO/ grouping for instance monomeric or partly polymerized styrene, vinyl esters such as the acetate, chloride, bromide, fluoride, etc... vinyl ketones, methvinyl ketones, vinylidene halides as the'chloride,

bromide and fluoride, acrylic and methacrylic esters, e. g., methyl acrylate, ethyl acrylate,

propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc.

As illustrative of the differences in properties resulting from interpolymerizing the itaconic esters of this invention with other polymerizable materials, the following is mentioned:

Diisoamyl itaconate which had been polymerized in the presence of 1% by weight benzoyl peroxide for about 3 days at approximately C. showed considerable plastic flow at that temperature. The same material when copolymerized under the same conditions with only 20% by weight of diallyl itaconate formed a firm, nonflowing gel (and set within 3 days to a hard, clear, colorless, heat-resisting copolymer that was insoluble in solvents, such as acetone and benzene, in which diisoamyl itaconate that similarly was polymerized alone was soluble.

As a further illustration of the differences resulting through copolymerization, the following is given.

A solution of 5 parts di-(isoamyl) itaconate and 95 parts ethyl methacrylate was treated with 0.25 part by weight benzoyl peroxide for 42 hours at 55 C. and for 24 hours at C. to give a hard, clear copolymer. This composition was sufiiciently ductile so that its flexural strength could notbe measured and had an impact strength (Dynstat) of 0.214 foot pound. Ethyl methacrylate, polymerized' alone under similar conditions, broke during a flexural strength test at 7450 pounds per square inch 'and had an impact strength of 0.135 foot pound. I

Similar copolymers with extremely high ductility were prepared from the following compositions and had the Dynstat impact strengths shown below.

Foot pounds 5 parts di-(isobutyl carbinol) itaconate 110 parts ethyl methacrylate 5 parts di-(amyl) itaconate 0145 95 parts ethyl methacrylate 5' parts di-(isobutyl carbinol itaconate) parts ethyl methacrylate 0.133

Various methods may be used to prepare the esters with which this invention is concerned. For example, they may be prepared by ester exchange reactions in the presence of a suitable inhibiting agent, such as phenolic bodies, and a suitable catalyst, the reaction proceeding as in an 'alcoholysis. This, in the preparation of, for instance, optically inactive diamyl itaconate, the reactants may comprise optically inactive amyl alcohol, dimethyl or diethyl itaconate, hydroquinone as an inhibiting agent and a catalyst such as metallic sodium, potassium carbonate, sulfuric acid, etc. The esters of this invention also may be prepared from itaconic nitrile by causingto react therewith a selected optically inactive amyl alcohol in the presence of water and an inorganic acid. -Or,' they may be made from itaconyl chloride and an optically inactive byanother alcohol.

amyl alcohoL- or by decomposition of a corresponding ester of citric or citraconic acids or one of their derivatives.

A preferred method of preparation is by direct esteriflcation of itaconic acid with the selected optically inactive amyl alcohol in the presence of an esterification catalyst, with or without the presence of other unreactive bodies to remove the water resulting from esterification. This method may be carried out continuously.

The mixed esters of this invention, that is itaconic esters in which both ester groups are different, also may be prepared in various ways. These mixed esters may be prepared,.for instance, 'by effecting reaction between itaconic monoester esters is from itaconic monoacid chloride and a selected optically inactive amyl alcohol, followed by direct esterification of the other acid radical be made by direct consecutive esteriiication of each of the carboxyl groups with difierent alcohols, or by treating itaconic diacid chloride first with one alcohol, then with another. They also may be prepared by saponiflcation of one group of an itaconic diester with alcoholic potassium hydroxide in the cold and either isolating the monoacid from the potassium salt for further reaction with the selected optically inactive amyl alcohol or causing the potassium salt to react directly with an alkyl sulfate corresponding to the ester desired.

In order that those skilled in' the art better mayunderstand how thepresent invention may be carried into eflect, the following illustrative examples are given of the preparation of these new esters and of various compositions comprising the same; All parts are by weight.

Diamyl itaconate I A solution of 52.9 parts optically inactive amyi 7 alcohol, 26 parts itaconic acid and 0.53 part concentrated sulfuric acid was refluxed for 17 hours. The reaction solution was added to an equal volume of water and the ester layer which separated was washed with sodium carbonate and distilled water. The crude ester was dried over .-anhydrous sodium carbonate and distilled under vacuum. Optically inactive diamyl itaconate was obtained as a fraction boiling at 163-170 C. at 17 mm. pressure. The polymeric itaconate was rather rubbery at room temperature.

Mixed amyl esters above and 186 parts mixed optically inactive amyl itaconic esters, boiling between 169-173 C. at 15 mm. pressure, were obtained; The esters These mixed esters also may were polymerized with 1- and 2% by weight benzoyl peroxide at 70 C.

Similarly prepared from optically inactive alcohols were di-(isobutyl carbinol) itaconate, boiling at 165-167 C. at 14-15 mm; di-(secondary butyl-carbinol) itaconate, boiling at 165- 168 C. at 16-17 mm; di-(diethyl carbinol) itaco- The production of'interpolymers with other" nate, boiling at 158-160.5 C. at 18 mm.; and di- (methyl propyl carbinol) itaconate, boiling at 156-160 C. at. 17-18 mm. pressure.

Example 1 g This example illustrates interpolymers produced with optically inactivediamyl itaconate.

Copiily- P t mer zaercen Temp. Characteristics Component tion benzoyl time in peroxide of copolymer hours (a) 50parts di-(amyl) 24 70 1 Clear, coloritaoonate less, slightly 50 parts dimethyl soft, tough.

itaeonate (b) 5 parts di-(amyl) 24 0.25 Clear, hard, taoonate transparent. parts ethyl Plus 18 65 methacrylate v (c) 60parts di-(amyl) 72 70 0.25 Soft, transitaoonate. lucent. 50 parts styrene (d) 50 parts di-(amyl) 72 70 1.0 Do.

itaeonate I 50parts styrene (a) fioparts di-(amyl) 48 70 1.0 Clear, coloritaconate less, rub- 50 parts vinyl I bery.

acetate 4 (I) 50parts xii-(amyl) 96 70 1.0 Clear, coloritaconate les, some- 50 parts methyl what rubmethacrylate bery, still. (9) 50parts (ii-(amyl) 48 70 1.0 Soft, rubbery.

itaoonate 50 parts methaerylic nitrile (h) SOparts (ii-(amyl) l 70 1.0 Gel, hard, ltaconate clear. 20 parts diallyl 72 70 itaoonate v Example 2 This example illustrates interpolymers produced with optically inactive di-(isoamyl) itaconate.

Copoly- P t v mer zaercen Temp. Characteristics Component tion a benzoyl time in peroxide copolymer hours a (a) 50 parts di-(iso- 24 70 1.0 .Hard, clear amyl) itaconate colorless. 50 parts diethyl nate (b) 50 parts di-(iso- M 70 1.0 Do.

amyDitgconate 50 parts dimethyl itaconate (c) 5 parts di-(iso- 42 55 0.25 Hard, clear, amyl) itaoonate transparent. 95 parts ethyl Plus24 85 methacrylate (d) 99 parts di-(iso- 24 70 1.0 Clear, coloramyl) itaoonate less, slightly so 1 art di-(octaecyl) itaoonate (e) 50 parts di-(iso- 24 70 1.0 Hard, clear,

amyl) itaconate colorless. 50parts diallyl itaconate (I). 50 parts di-(isw 24 70 1.0 Translucent,

, amyl) rtaoonate hard.-

50 parts glycol dimethacrylate '50 parts di-(iso- 24 70 1.0 Translucent, amyl)-itaconate s If: g h t l y so 50parts methallyl methacrylate I (h) 20vparts di-(iso- 48 70 1.0 Soft, clear.

amyDitaconate 10 parts diallyl oxalate Example 3 is illustrated in this example.

Cupoly- P t mer zaercen Temp. Characteristics Component tion 9 benzoyl time in peroxide hours (a) parts di-(diethyl 42 0. 25 Clear, hard.

cztarbmol) itacona e 95 parts ethyl Plus24 .methacrylate (b) 5 parts di-(methyl 23 55 0.25 Transparent, propyl carbinol) clear, hard. itaconate 95 parts ethyl Plus24 85 methecrylate (c) 5 parts di-(diethyl 18 55 0. 25 Hard, transcagbinol) itaconluccnt. a

95 parts methyl Plus 24 85 methacrylate (d) 6 parts til-(methyl 18 55 0. 25 Do.

propyl carbinol) ltaconate 95 parts methyl Plus 24 85 methacrylate (e) 20 parts di-(isobu- 48 70 1.0 Soft, clear. tyl carbinol) itaconate 20 parts diallyl oxalate (f) 5 parts di-(isobu- 42 55 0.25 Transparent tyl carbinol) itaclear, hard. conate 95 parts ethyl Plus 24 85 methacrylate Example 4 cases one of the components being an optically inactive itaconic ester of this invention.

Component Copolymemetion time in hours Temp., 0.

Percent benzoyl Characteristics of oopolymer 50 parts di-(amyl) itaconate 25 parts vinyl ace tate 25 parts methyl methacrylate 33% parts di-(isoamyl) itaconate 33% Parts dimethy itaconate 33% parts diethyl itaconate 49 parts di-(lsoamyl) itaoonate 49 parts dimethyl itaconate 2partsdioctadecyl itaconate 33% parts di-(lsoamyl) itaconate 33% parts diethyl itaconate 33% parts dihexyl itaconate 33% parts di-(isoamyl) itaconate 33% parts styrene 33% parts vinyl acetate 37% parts di-(isoamyl) itaconate 37% parts vinyl ace e 12% parts ethyl acrylats 12% parts propyl methacrylate 43 parts di-(isoamyl) itaconate 43 parts dimethyl itaoonate 14 parts glycol dimethacrylate 43 parts di-(isoamyl) itaconate 43 parts diethyl itaoonate 14 parts methallyl methacrylate Translucent,

rubbery.

Soft, clear, oolorless.

Clear, colorless, slightly soft.

Clear, colorless, soft, rubbery.

Very viscous clear.

Clear, colorless, hard.

Hard, clear,

colorless.

Component Copolymaritaltion time in hours Peroent benzoyl Characteristics of copolymer peroxide '16 parts di-(iso- 43 parts di-(isoamyl) itaconate 43 parts dimethyl itaoonate 14 parts methallyl methacrylate 33% parts dl-(isoamyl) ltaconate 33% parts diallyl itaoonate 95 parts ethyl methacrylate 0.1 part diallyl itaconate 5 parts parts di-(isobutyl carbinol) itaconate 95 parts ethyl methacrylate 0.1 part diallyl itaconate amyl) itaconate 43 parts diethyl itaconate 14 parts diallyl itaconate maleate amyl) itaconate 15 parts vinyl acetate 5 parts diallyl oxalate 15 parts di-(isooutyl carbinol) itaconate 10 parts diallyl oxalate 5 parts ethyl acrylate 15 parts di-(1so-. amyl) itaconate 10 parts diallyl oxalate 5 parts ethyl acrylate Plus 24 Plus 24 Plus 24 0. 25 Hard, transluoont.

0.25 Transparent,

clear, hard.

1.0 Clear, colorless, slightly soft.

1. 0 Hard, clear.

Soft.

1. 0 Soft, clear.

1.0 Soft, rubbery.

partial polymer.

itaconic ester of this invention.

Copoly- P t merizaercen Temp. Characteristics Com nent tion s benzoyl no time in peroxide of copolyme".

hours (a) BOpartsPdi-(lso- 72 70 1.0 Hard,transluamyl) itaoonate cent. 50 parts diallyl itaconato (b) 50 parts P di- 36 70 1.0 Soit,cloar.

(amyl)itsconate 50 parts butyl methaorylate (c) 50partsPdl-(iso 35 70 1.0 Slightly soft, 1 amyl) itaconate translucent. 50 parts ropyl metnacry ate (d) 50partsPdi-(iso- 48 70 1.0 Slightly solt, amyl) itaconate clear. 50 parts diethyl itaconate (e) 50 parts dl-(iso- 48 70 1.0 Translucent, amyl) itaconate hard. 50 parts I methylftaeonate Copolymerlzation time in hours Percent benzoyl namri (1D A Characteristics Component (1) 43 parts P di(iso 1.0 Hard, clear.

amyl) itaconate 43 parts dimcthyl itaconate 14 parts P ethyl acrylate (g) 60 parts P di-(isoamyl) itaconate 50 parts P vinyl acetate (h) 54 parts P di-(isoamyl) itaconate 33% parts P vinyl acetate 33% parts diethyl itaconate l. Translucent,

rubbery.

1.0 Soft, clear.

Translucent,

tough.

48 70 1.0 amyl) itaconate 50 parts P methyl methacrylate (j) 50 parts P di-(isoamyl) itaconate 50 parts P styrene (k) 50 parts P di-(isoamyl) itaccnate 50 parts P ethyl acrylate (I) 50 parts P di-(isoamyl) itaconate 50 parts P methyl acrylate (m) 50 parts P di-(isoamyl) itaconate 50 parts P butyl methacrylate (n) 50 parts P di-(isoamyl) itaconate 50 parts P isobutyl methacrylate (o) 50 parts P (ii-(isoarnyl) itaconate 50 parts P propyl itaconate (p) 50 parts P di- (amyl) itaconate Translucent,

viscous.

Clear, rubbery.

Translucent,

soft.

Translucent,

Slightly soft, translucent.

Slightly translucent,tough.

70 l. 0 Translucent,

bard.

. 48 70 Soft, clear.

Slightly soft, translucent.

acrylate (r) 33% parts di-(isoamyll itaconate 33% parts methyl methaerylate 33% arts P dimet ylitaponate (w) 50 parts (ll-(Boamyl) itaconate 60 parts P styrene (1) 33% parts di-(iso amyl) itaconate 33% parts P vinyl acetate 33 partsPdiethy itaconatc (v) 50 parts P di-(isoamyl) itaconata 50 parts methallyl methacrylate (z) 50 parts P di-(isoamyl) ltaconate 50 parts glycol dimetliacrylate (an) 50 parts P d1- (amyl) itaconate 50 parts methallyl niathacrylate Translucent,

soft.

Soft, translu cent.

l. 0 Clear, rubbery.

Hard, translucent.

l. 0 Translucent,

viscous.

Slightly soit,

clear.

The diallyl itaconate, diallyl oxalate, diallyl maleate, glycol dimethacrylate, and methallyl methacrylate inthe above examples may be increased or may be replaced in whole or in part by slightly soft.

nature.

monomeric or partly polymerized materials, in-

substances such, for instance, as allyl and methaliyl esters of pclybasic acids, for example, diallyl carbonate, diallyl malonate, diallyl succinate, diallyl glutarate, diallyl adipate, diallyl pimelate, diallyl suberate, diallyl azelaate, diallyl sebacate,

'diallyl alpha dimethyl malonate, diallyl alpha allyl malonate, diallyl fumarate, diallyl phthalate, diallyl tartrate, triallyl citrate, triallyl carballylate, diallyl citraconate, diallyl mesacc'nate, diallyl glutaconate, diallyl hydromiicate, diallyl glutinate, tetra-allyl symmetrical ethane tetracarboxylate, etc.; by other polyhydric alcohol and unsaturated alcohol esters of acrylic and methacrylic acids, for example glycol acrylate, allyl acrylate, allyl methacrylate, methallyl acrylate, etc.; or by mixtures of such substances.

The optically inactive amyl itaconates of this invention, as well as the interpolymers obtained by copolymerizing these itaconates with other polymerizable bodies have a wide range of properties. Their hardness and solubilities may be varied over a considerable range from fluid compgsitions of varied intrinsic viscosity or soft, fl xible bodies to hard rigid masses that can be swelled or dissolved in many .volatile and nonvolatile solvents, even those of a hydrocarbon By suitable selection of the starting terpolymers can be obtained in an insoluble infusible state practically resistant to the destructive eifect of other chemical bodies such as acids,

bases, solvents and the like.

When a plasticizing effe'ct is desired in some other synthetic or natural plastic or potentially plastic material, the it-aconic esters of this invention are particularly suited for that purpose. High molecular weight'bodies, such as polyvinyl chloride, cellulose esters such as the acetate, propionate, butyrate, etc., cellulose ethers such as methyl cellulose, ethyl cellulose, benzyl cellulose, polymerized methyl methacrylate, polystyrene, etc., may be plasticized by incorporating therewith an optically inactive itaconic ester in monomeric, partially polymerized or completely polymerized state, in the presence or absence of a catalyst such as benzoyl peroxide when the monomeric or partially polymerized forms are used. The itaconic ester may be incorporated into the high molecular weight body by simple mechanical agitation or by the use of mutual solvents, followed by the standard mechanical processes known to the plastics art. These bodies then may be subjected to further heat and pressure treatment if desired.

The esters of this invention may be converted to polymers or interpolymers in molds with or without the application of pressure, in the presence or absence of a material which is a solvent for the monomer but not for the polymer, or one which is a solvent for both monomer and polymer, or one which is a solvent for either the monomer or polymer so that spongy or granulated polymeric modifications are obtained.

The solid, thermoplastic polymers and copolymer's of this invention, with or without modifying agents, may be used in injection, compression, or transfer molding processes to make numerous articles for industrial, technical and novelty use and other applications.

As modifying agents various fillers may be used, for example-wood flour, alpha flock, sand, asbestos, mica,'paper, cloth, cellulose derivatives such as cellulose itself, regenerated cellulose, cellulose esters, cellulose .etliers, natural and synthetic filaments or fibers, etc., in continuous,

shredded, or comminuted form. Pigments, dyes, opaclfiers, plasticizing substances, such as dibutyl phthalate, esters of monobasic and polybasic saturated and unsaturated acids, esters of aromatic monobasic and polybasic acids, etc., may be incorporated into the polymers and copolymers of Synthetic and natural resins, gums, oils, waxes, polyhalogenated aromatic derivatives, etc., may likewise be aded as modifying agents.

In solvents, or without solvent utilizing a melt process, the fusible polymers may be used in adhesive and laminating applications, to bond paper, cloth, wood, mica flakes, glass sheets, rubber sheets, etc., fibrous materialssuch as silk, asbestos, glass fibers, synthetic fibers in filament, thread or fabric (woven or felted) form, etc., cellulose derivatives in sheet, comminuted or fiber form, etc. In the form of liquid coating compositions such as varnishes, lacquers, enamels, etc., they find application in surface protective coatings, such as for walls, desks, wire, concrete, porcelains, etc. In a fiowable condition without the use of solvents they. may be used as impregnants for many porous bodies, such as cork, pottery. felts, or fabricated bodies withinterstices, such as the windings of electrical coils, netted fiber, interwoven fibrous materials, etc.

When the monomers of this invention are cothis invention to modify the same.

polymerized with, for example, diallyl ltaconate in the. presence of another non-polymerizable body which acts as a solvent for these monomers, there results a homogeneous gelled material which firmly binds the solvent so as to reduce to a minimum evaporation losses of the solvent. Illustrative of non-polymerizable bodies which thus may be gelled are butyl alcohol, benzene, ethylene dichloride, the monohalogenated aromatic hydrocarbons or mixtures of halogenated aromatic, hydrocarbons, ethylene glycol, mineral oils including lubricating oils, etc.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A composition comprising-the product of polymerization of a mixture containing di-(isobutyl carbinol) itaconate and ethyl methacrylate in the ratio of, by weight, 5 parts of the former to parts of the latter,

2. The method of producing a clear, hard, organic plastic material which comprises forming a mixture containing monomeric di-(isobutyl carbinol) itaconate and monomeric ethyl methacrylate in the ratio of, by weight, 5 parts of the former to 95 parts of the latter and, in addition to said monomers, a small amount of benzoyl peroxide as a polymerization catalyst, and heating the said mixture to obtain a clear, hard interpolymerization product.

GAETANO F. DALELIO.

CERTIFICATE OF commoner. Patent No. 2 ,279 ,885. April In, 19 2- GAE'I'ANO F. D'ALELIO.

s It is hereby certified thsterror appears in the printed. specification of the above numbered patent requiring correction as follows: Page 5, first coluzqnfiine 15*, in the table Exaiilple for "1/ v parts" read --55 1/5- perts and tmt the skid Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent bffic e..

Signed 51 d sealed this 16th d'ay of June, 1;. D.".19b.2.

r v -Henry Van Arsdale; (S681) Acting Commissioner of Patents. 

